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Thread: Gowlandflex question

  1. #21
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    Re: Gowlandflex question

    Unlike some Gowlandflexes, yours has matched viewing and taking lenses. That doesn't mean the actual focal lengths are identical - there can be sample variation - but it means that a large focal length mismatch is unlikely. If they are the same or very close to it, then the mismatch will persist throughout the focusing range.

    I think the likeliest explanation is that the taking and viewing lenses are not properly adjusted to match flange focal distances. Since you're reporting that the on-film image is back-focused relative to what you see on the GG, it appears that the taking lens needs a bit more extension. Certainly I would start with the viewfinder vs rear GG test that Tin Can proposes, and see what you find. But if the error that you reported from your initial film tests is confirmed, I would try adjusting the mounting of the taking lens before messing with the mirror.

  2. #22

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    Re: Gowlandflex question

    Quote Originally Posted by Oren Grad View Post
    Unlike some Gowlandflexes, yours has matched viewing and taking lenses. That doesn't mean the actual focal lengths are identical - there can be sample variation - but it means that a large focal length mismatch is unlikely. If they are the same or very close to it, then the mismatch will persist throughout the focusing range.

    I think the likeliest explanation is that the taking and viewing lenses are not properly adjusted to match flange focal distances. Since you're reporting that the on-film image is back-focused relative to what you see on the GG, it appears that the taking lens needs a bit more extension. Certainly I would start with the viewfinder vs rear GG test that Tin Can proposes, and see what you find. But if the error that you reported from your initial film tests is confirmed, I would try adjusting the mounting of the taking lens before messing with the mirror.
    Thank you for weighing in - I appreciate it. I am going to run through a few low-risk tests tonight though fear that this may quickly jump above my comfort level.

  3. #23

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    Re: Gowlandflex question

    I just compared the viewing ground glass and the taking ground glass from head and shoulders head portrait distance (about six feet or so) and waste up portrait (about 12 feet) - from both distances, the picture taking and viewing ground glass are completely unpaired.

    I suspect that the previous owner either lived with the focusing issue and compensated for it (achieve guesstimate focus with the viewing lens and rack it out a bit before exposure) or shelved this camera long ago.

    An odd discovery - the picture taking ground glass is far easier to achieve focus on. I think that the reflex mirror may need a real cleaning.
    Last edited by joelio; 10-Nov-2020 at 12:32. Reason: Typo

  4. #24

    Join Date
    Apr 2020
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    300

    Re: Gowlandflex question

    I admit total ignorance of all things Gowland... but are both the ground glasses oriented the same? ie, frosted side towards the lens (or not) on both assemblies?

  5. #25

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    Re: Gowlandflex question

    Quote Originally Posted by grat View Post
    I admit total ignorance of all things Gowland... but are both the ground glasses oriented the same? ie, frosted side towards the lens (or not) on both assemblies?
    No luck. That would have made my year - I’d love an easy fix!

    Thank you.

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